It does work, but I cannot filter just one category with that plugin. Right now when I search a movie here; http://filmfestival.dk/en/category/programme/ the results get another layout than the default search, it only search one category, etc. These settings aren’t possible with the plugin…

In your search template you can try a query_posts with custom field data.
something like this (put this before the loop):<?php query_posts('meta_key=movie&meta_value='.$s); ?>
the $s is the global search string produced by WordPress.

Try it with only the meta value.<?php query_posts('meta_value='.$s); ?>
Im going to check if I can make it work on my server. Why is the information like: movie title, director and so on not in the posts?

You could create your own search page to show your “film” search results. And the normal search.php for al the other search results
or multiple loops. One for the normal search results and one for the meta search results:

@keesiemeijer Hi – having looked around for ages I came across your solution which was great and worked although I couldn’t get it quite right.

I’m using a category as a staff list for a company. I have an A-Z display of thumbnails etc which are all custom fields including their first and last name {2 separate custom fields}. So by using your idea <?php query_posts('meta_value='.$s); ?> works great if people enter say a first or last name, but if someone types in both {to the search box}, no results are displayed as it’s now looking for a first and lastname.